Latch



Nov. 19, 1963 c. B. KIMBLE 3,

LATCH Filed Apri1 7, 1961 mmvmn. CREIGHTON B. KIMBLE United States Patent 3,111,338 LATCH Creighton B. Kimble, South Plainfield, N.J., assignor, by mesne assignments, to Lockheed Aircraft @orporation, Burbank, Caliti, a corporation of California Filed Apr. 7, 1961, Ser. No. 101,421 Claims. ((11. 292-111) This invention relates to latches for releasably fastening a movable member such as a door or drawer to a frame and more particularly to an improved latch with a novel pawl and actuating mechanism controlled by rotation of a handle on the latch housing to pull a movable member firmly against its associated frame and hold the two elements in positive engagement.

In packaging large, electronic equipment, it is customary to employ multi-drawer cabinets with the various electronic equipment components being physically arranged in separate modules or units each mounted on a chassis drawer which is slidable in and out of the cabinet. The design requirements for this type of electronic packaging often includes making the drawers practically fluid tight so as not to leak in the presence of moist air, salt water spray or rain. This obviously requires the drawers to be held firmly in the closed position. Also, with this type of electronic packaging the units are sometimes electrically coupled through connectors associated with each drawer which make contact by closing the drawer. The force required to completely close drawers equipped with such connectors makes use of force augmentation such as may be provided by a tensioning latch desirable. The present invention is specially suited for locking cabinet drawers of the types discussed above but may be used to good advantage in any application where a strong and reliable tension latch is needed.

t is an object of this invention to provide a latch with combined tension locking and safety catch features. The latch will automatically engage a catch to hold a drawer or door in a nearly closed position and pull the same to a firmly closed position by rotation of the latch handle.

It is another object of this invention to provide a dependable latch requiring only two moving parts with the holding force in the locked position being provided largely by the latch housing.

Another object of this invention is to provide a latch which may be economically manufactured and assembled. The latch may be made entirely of stamped and die cast parts with little or no machining.

Still another object of this invention is to provide a latch with a handle which may be either rotated for actuating the latch or locked and used as a convenient handgrip for moving the drawer or the like on which the latch is mounted. Initial rotation of the handle from the locked position removes the closing pressure exerted by the latch with further rotation being required for releasing the latch.

Further and other objects will become apparent from the reading of the following detailed description especially when considered in combination with the accompanying drawing wherein like numerals refer to like parts.

hi the drawing:

1 FZGURE 1 is a fragmentary sectional side view of the atc FIGURE 2 is a sectional view taken on line 2--2 of FIGURE 1; and

FIGURE 3 is a fragmentary side view taken of FIG- URE 2.

Referring to the drawing there is shown in FIGURE 1 a latch housing 10 secured to a movable member 11 such as a drawer or door by suitable means such as bolts 12. A frame '13 associated with movable member 11 and representing a cabinet or door jamb is also shown having a "ice catch 14 secured thereto. Catch 14 is positioned relative to the latch so as to engage the hook-end 15 of pawl member 16.

Latch housing 10 may be a solid block of material cast from metal, synthetic plastic or the like. Housing 10 is provided with at least one planar or flat external surface 17 transversely of its mounting face '18. A cavity or opening 19 of generally rectangular cross-sectional shape is formed in housing 11% at face 18 to index with an opening 24 in movable member 11 on which the latch is mounted. Pawl member 16 is slidably received within opening 19 with its hook-end 15 projecting outwardly from latch housing 1% and through member 11. The narrow transverse cross-sectional dimension of pawl member 16 is only slightly less than the width of opening 19 in the latch housing so as to prevent appreciable lateral movement of the pawl member relative to the housing. The wide transverse cross-sectional dimension of pawl member 16 is, however, substantially less than the height of the generally rectangular opening '19 in the housing except that the aft end 21 of the pawl member is enlarged at 22 to provide a protuberance mating with the opening. The enlargement of the aft end of pawl member 16 being on the upper edge with the lower edge 24 and back edge 25 being generally fiat allows the pawl member to swing relative to the housing only when partially withdrawn from the housing as indicated by the dotted line positions a and b in FIG- URE 1. When the pawl member is bottomed or seated against the aft end of the opening it is held against rotation by the housing. The aft corners 26 and 27 of the pawl member are rounded to provide the necessary clearance for rotation of the pawl member within the housing opening when partially withdrawn therefrom and to provide cam surfaces which may engage the wall of the opening and provide a fulcrum about which pawl member 16 is rotated to and from the latched position shown as position c in FIGURE 1.

A bore 23 through the generally flat side 17 of latch housing 1i communicates with the generally rectangular opening 19 to support a shaft 29 for rotation about an axis generally normal to the plane of the rectangular opening 19. An eccentric pin 30 is carried on shaft 29 and projects into opening 19 to engage a cam slot 31 formed in pawl member 16. Shaft 29 is held in the latch housing by a retaining ring 32 which rides on a shoulder 33 formed in bore 28. Retaining ring 32 is compressed when inserting shaft 29 in bore 28 and then released to seat against the shoulder, permanently locking both the shaft and pawl member in the housing.

A handle 34 is fixedly secured to shaft exteriorly of the housing by suitable means such as bolt 35. Rotation of shaft 29 by means of handle 34 controls movement of pawl member 16.

Cam slot 31 in pawl member 16 is cut from the lower edge 24 of the pawl member with a generally straight back cam surface and a V-shaped forward sloping front cam surface to form a forwardly diverted generally triangular shaped opening. The shape of cam slot 31 and its location forwardly of the enlarged aft end 21 of the pawl member provides efiicient transfer of forces from the eccentric pin to the pawl member in obtaining sequential linear and rotational movement of the pawl member to and from the locked position. The V-shaped forward surface of cam slot 31 is further useful in causing the eccentric pin to rotate and reduce shearing loads thereon in the event excessive forces are applied to the hook-end of the pawl member accidentally or otherwise when the pawl member is partially withdrawn from the housing.

Vi/hile pawl member 16, in the locked position, is held from rotating by housing 11 and from rectilinear movement by eccentric pin 3%), as the pawl member is withdrawn from the opening in the housing for releasing the latch, it becomes free to rotate within the limits of the housing opening. Accordingly, a leaf spring 36 is secured at one end in a groove in the enlarged aft end of pawl member 16 by suitable means such as bead 37 to press against the housing in the opening and urge the pawl member in a direction maintaining eccentric pin 31) in engagement with the surface of cam slot 31.

Referring specifically to FIGURES 2 and 3 an arcuate groove 41) is formed in the generally flat side 17 of hous ing 19 concentric with bore 28. A coil spring 41 is carried in the arcuate groove. A detent 42 carried on handle 34, also rides in the groove to engage compression spring 41 and thereby urge the handle, when unlocked, to assume the dotted line position d rather than the dotted line position e shown in FIGURE 1. The segment of the total handle movement between a and e rotates the pawl member to completely disengage the latch from catch 14. If desired, a small rivet-like piston 51 may be inserted in the end of compression spring 41 so that detent 42 on the handle will drive the piston to compress the spring rather than have the detent engage the spring directly.

It should be noted that spring 41 and piston 51 are retained in groove 40 by the wide flange 43 on the lower end of the handle. It should also be noted that detent 42 is provided on both sides of the handle so that the handle may be used interchangeably for both left and right hand latches.

The free end of handle 34 is bifurcated to receive a hook lever 45 for engaging a catch 46 on movable member 11. This locks the latch and permits use of the handle as a handgrip for moving member 11. Hook lever 45 is provided with a notch 47 which seats on a crossbar 48 in the bifurcated end portion of handle 34. Hook lever 45 is urged into its locking position by a spring 49 carried in a bore in the handle. Spring 49 engages the end 50 of hook lever 45 aft of crossbar 48. Hook lever 45 and spring 49 cooperate to hold each other assembled in the handle. Hook lever 45 may be released from catch 46 simply by pressing down on the portion projecting from the handle, causing spring 49 to be compressed. It should be noted that hook lever 45 will automatically engage catch 46 by merely pushing the handle to the closed position.

The first 90 of handle rotation to position (I as shown in FIGURE 1 causes pawl member 16 to move outwardly from the housing to a partially withdrawn position indicated as position a. As pawl member 16 is moving outwardly from the housing it is freed to rotate Within the limits allowed by the latch housing; hence, it may ride up on catch 14 as illustrated. If member 11 were moved away from frame 13 as handle 34 is being rotated to position a, pawl member 16 would not rotate as illustrated but would simply move rectilinearly outwardly from the latch housing with its hook in contact with the catch. Only by further rotation of handle 34 from position d to position e against the action of compression spring 40 is eccentric pin 30 caused to rotate pawl member 16 to the unlatched position b. With the handle in position e, the latch is completely disengaged from catch 14 allowing member 11 to be moved away from frame 13. After pawl member 16 is moved out of contact with catch 14, handle 34 is allowed to return to position d. To close the movable member, a door or drawer as the case may be, it is simply shoved toward the closed position. When pawl member 16 strikes catch 14 it will raise up and ride over the catch and become automatically engaged to retain the movable member in a partially closed position. To completely close the movable member relative to its associated frame 13, handle 34 is simply rotated from position d to the solid line locked position shown in FIGURE 1.

While a specific embodiment of the latch has been shown and described it should be understood that certain alterations, modifications and substitutions may be made to the instant disclosure without departing from the spirit 4 and scope of the invention as defined by the appended claims.

I claim:

1. A handle latch for releasably securing a movable member to a frame comprising, a latch housing carried on the movable member, said housing having an elongated cavity formed therein open at one end, a pawl member received within said cavity and extending outwardly beyond the housing, said pawl member having the end thereof within said cavity enlarged to generally mate with said cavity, said pawl member having a slot cut therein intermediate its ends, said housing having a bore formed therein and intersecting said cavity, a shaft received Within said bore, an eccentric pin carried on said shaft within the housing and engaging the slot in said pawl member, a handle having one end thereof secured to said shaft externally of the housing for rotating the shaft and effecting both linear and rotational movement of said pawl member, the free end of said handle being bifurcated, a hook member received in the bifurcated end of said handle for pivotal movement, a catch carried on said movable member, and spring means cooperating with said hook member to secure the spring and hook assembly in the handle urging said hook member in the direction for engaging said catch to hold the handle from rotating.

2. A handle latch as defined in claim 1 including spring means in the cavity urging said pawl member in one direction.

3. A latch as defined in claim 1 including an arcuate groove formed in the outer wall of the housing generally concentric with said shaft, a compression spring carried within said groove and retained therein by said handle, a detent on the handle arranged to ride in said groove and engage said compression spring and oppose rotation of said handle throughout only a portion of its total swinging movement.

4. A handle latch comprising a housing, said housing having an elongated generally rectangular shaped cavity formed therein open at one end, opposed Walls of said cavity forming ways, a pawl member received within said cavity and extending outwardly beyond the housing, said pawl member having the end thereof within said cavity enlarged to engage said Ways and'allow only rectilinear movement of said pawl member when bottomed in the cavity to secure the latch, the enlarged end of said pawl member providing a fulcrum about which the pawl member may rotate when at least partially withdrawn from the housing for releasing the latch, said pawl mem her having a. forwardly diverging generally triangular shaped cam slot cut therein intermediate its ends, the aft wall portion of said cam slot being generally normal to said ways, said housing having a bore formed therein and intersecting said cavity, a shaft received within said bore, an eccentric pin carried on said shaft within the housing and engaging the cam slot in said pawl member, and a handle having one end thereof secured to said shaft externally of the housing for rotating the shaft and moving the eccentric pin to effect both linear and rotational movement of said pawl member.

5. A latch comprising a housing, said housing having a generally rectangular shaped cavity formed therein open at one end, opposed walls of said cavity forming ways, a pawl member received within said cavity and arranged to bottom therein to secure the latch and extend outwardly beyond the housing, a protuberance formed on the end of said pawl member received in said cavity and acting between said housing and pawl member allowing only rectilinear movement of the pawl member when bottomed in the cavity to secure the latch, said protuberance slideably engaging said ways to provide a fulcrum about which said member may rotate when at least partially withdrawn from the housing for releasing the latch, said pawl member having a slot cut therein intermediate its ends, said housing having a bore formed therein and intersecting said cavity, a shaft received within said bore,

an eccentric pin carried on said shaft within the housing and engaging the slot in said pawl member, and handle means carried on said shaft externally of the housing for rotating the shaft and moving said pawl member.

6. A latch comprising a housing, said housing having a generally rectangular shaped cavity formed therein open at one end, opposed walls of said cavity forming Ways, a pawl member received within said cavity and extending outwardly beyond the housing, a protuberance formed on the end of said pawl member received in said cavity and locking said pawl member against rotation when bottomed in said cavity for securing the latch, said protuberance slideably engaging said ways to provide a fulcrum about which the pawl member may rotate when at least partially withdrawn from the housing for releasing the latch, said pawl member having a slot cut therein intermediate its ends, said housing having a bore formed therein and intersecting said cavity, a shaft received with said bore, an eccentric pin carried on said shaft within the housing and engaging the slot in said pawl member, a handle secured at one end to said shaft externally of the housing for rotating the shaft and effecting both linear and rotational movement of said pawl member, and manually operable means releasably locking said handle and shaft against rotation relative to said housing.

7. A latch comprising a housing, said housing having a generally rectangular shaped opening formed therein, a pawl member received within said opening and extending outwardly beyond the housing, said pawl member having the end thereof within said housing enlarged to generally mate with said opening and cooperate with the housing to provide a fulcrum about which the pawl member may rotate but only when at least partially withdrawn from the housing, said pawl member having a slot cut therein adjacent the enlarged end, said housing having a separate opening formed therein transversely of the first-mentioned opening, a shaft received within the second opening, an eccentric pin carried on said shaft Within the housing and engaging the slot in said pawl member, and handle means carried on said shaft externally of the housing for rotating the shaft and efiecting both linear and rotational movement of said pawl member, an arcuate groove formed in the outer wall of the housing generally concentric with said shaft, a compression spring carried within said groove, and a detent on the handle means arranged to ride in said groove and engage said spring and oppose rotation of said handle means.

8. A latch as defined in claim 7 including spring means within the housing urging said pawl member in one direction.

9. A latch comprising a housing, said housing having an elongated open cavity formed therein, a pawl member received within said cavity and extending outwardly beyond the housing, said pawl member having the end thereof within said housing enlarged to generally mate with said cavity, said pawl member having a slot cut therein intermediate its ends, said housing having a bore formed therein and intersecting said cavity, a shaft received within said bore, an eccentric pin carried on said shaft within the housing and engaging the slot in said pawl member, handle means carried on said shaft externally of the housing for rotating the shaft and effecting both linear and rotational movement of said pawl member, an arcuate groove formed in the outer wall of the housing generally concentric viu'th said shaft, a compression spring carried within said groove and retained therein by said handle means, and a detent on the handle means arranged to ride in said groove and engage said compression spring and oppose rotation of said handle means.

10. A latch as defined in claim 9 including spring means in the cavity urging said pawl member in one direction.

References Cited in the file of this patent UNITED STATES PATENTS 2,021,957 Gregg Nov. 26, 1935 2,609,268 Nye Sept. 2, 1952 2,926,05 6 Newcomer et al Feb. 23, 1960 FOREIGN PATENTS 14,365 Great Britain 1908 

5. A LATCH COMPRISING A HOUSING, SAID HOUSING HAVING A GENERALLY RECTANGULAR SHAPED CAVITY FORMED THEREIN OPEN AT ONE END, OPPOSED WALLS OF SAID CAVITY FORMING WAYS, A PAWL MEMBER RECEIVED WITHIN SAID CAVITY AND ARRANGED TO BOTTOM THEREIN TO SECURE THE LATCH AND EXTEND OUTWARDLY BEYOND THE HOUSING, A PROTUBERANCE FORMED ON THE END OF SAID PAWL MEMBER RECEIVED IN SAID CAVITY AND ACTING BETWEEN SAID HOUSING AND PAWL MEMBER ALLOWING ONLY RECTILINEAR MOVEMENT OF THE PAWL MEMBER WHEN BOTTOMED IN THE CAVITY TO SECURE THE LATCH, SAID PROTUBERANCE SLIDEABLY ENGAGING SAID WAYS TO PROVIDE A FULCRUM ABOUT WHICH SAID MEMBER MAY ROTATE WHEN AT LEAST PARTIALLY WITHDRAWN FROM THE HOUSING FOR RELEASING THE LATCH, SAID PAWL MEMBER HAVING A SLOT CUT THEREIN INTERMEDIATE ITS ENDS, SAID HOUSING HAVING A BORE FORMED THEREIN AND INTERSECTING SAID CAVITY, A SHAFT RECEIVED WITHIN SAID BORE, AN ECCENTRIC PIN CARRIED ON SAID SHAFT WITHIN THE HOUSING AND ENGAGING THE SLOT IN SAID PAWL MEMBER, AND HANDLE MEANS CARRIED ON SAID SHAFT EXTERNALLY OF THE HOUSING FOR ROTATING THE SHAFT AND MOVING SAID PAWL MEMBER. 